Sanding machine



J. GALBRAITH.

SANDING MACHINE.

APPLICATION FILED APR. 2a. 1921.

1,430,370. Patented sept. 26, 1922.

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J. GALBRAITH. SANDING MACHINE-` APPLIcATloN man Amma. 192:.

Patented Sept. 26, 1922.

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SANDING MACHINE.

APPLICATION FILED APR. 2a, 192|.

l A 30,' 370. Patented Sept. 26, 1922.

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`SNDING MACHINE.

APPLICATION FILED APR. 23. 192|.

Patented Sept. 26, 1922.

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SANDING MACHINE. APPLICATION man APAR. 23. Y1921.

Patented Sept 26, 1922.

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rric- JOHN GALBRAITH, OF ST. PAUL, MINNESOTA.

SANDING MACHINE.

Application filed April 23, 1921.

To @ZZ Iwhom t may concern.'

Be it known that I, JOHN GALBRAITH, a citizen of the United States,resident of St. Paul, county of Ramsey, State of Minnesota, haveinvented certain new and useful Inmprovements in Sanding Machines, ofwhich the following is a specification. y The object of my invention 1sto provide an improved form of guide bar for the sanding head or shoe tothe end that the movement of the shoe or head may be more uniform andeven.

A further object is to provide an improved form of drive, and means forregulating the stroke or' travel.

@ther objects of the invention will appear from the following detaileddescription.

In the accompanying drawings forming part of this specification,

Figure 1 is a side elevation of a machine embodying my invention;

Figure 2 is a plan view of the same;

Figure 3 is a detail view of a portion of the machine, showing themechanism for adjusting the length of the stroke;

Figure 4 is a sectional view on the line 4-4 of Figure 3;

Figure 5 is a sectional view on the line 5--5 of Figure 4;

Figure 6 is a transverse sectional view showing the construction of theguide bar;

Figure 7 is a view on the section line 7-7 of Figure 6;

Figure 8 is a sectional view on the line 8 8 of Figure 4;

Figure 9 is a side view of the guide bar and the mechanism for raisingand lowering it;

Figure 10 is a sectionalview on the line 10-10 of Figure 9;

Figure 11 is a sectional view showing the means for raising and loweringthe worksupporting table;

Figure 12 is a sectional. view on the line 12-12 of Figure 11; y

Figure 13 is a. transverse sectional view showing the lever for raisingand lowering the guide bar;

Figure 14 is a sectional view on the line 14-14 of Figure 2.

ln the drawing, 2 represents the frame of the machine, in which thesanding mechanism is mounted. At one end of the machine is drive -shaft3 having at one end fixed and loose pulleys 4 and 5 and at the sandingSerial No. 464,056.

the table having suitable anti-friction rollers 13 to rest` and rollupon these rails, as usual in machines of this kind.. The rails aresupported by upright screws 14 Ajournaled in the machine frame and theupper ends of these screws are geared to a horizontal shaft 15 having anoperating crank 16 lby means of which the screws may be revolved and thetable and the supporting rails raised and lowered in ythe machine frameto adapt the machine for pieces of work of different sizes and shapes.All this mechanism is of ordinary 'construction inV machines of thistype. f f

A driving belt 17 connects the drive shaft 3 with a pulley 18 on ashaft19 that is journaled in the machine frame and has a belt connection20 with a pulley 21 loosely mounted on a sleeve 22 that isjournaled inbearings in the machine frame. The pulley 21 has a clutch 4member 24secured to the hub thereof and a clutch member 24a is secured to thesleeve 22 by suitable means, such as a set screw 26, and carries clutchwings 27 pivoted at 28 and adapted to engage an internal frictionsurface on the clutch member 24, being ynormally held out of contactwith said surface by the tension of a spring 29. A bar 30 is mounted inthe clutch member 24a and'has one end projecting between the wings 27 inposition to separate these wings and cause them to engage the internalfriction surface of the clutch member 24 when the clutch member 25 whichis slidably mounted on sleeve 22 is operated.

A rod 31 is connected with the clutch member 25 and is provided witha'crank arm 32 to which the operating bar 33 is attached and adapted formovement longitudinally to oscillate the arm 32, rock the rod 31 andshift the clutch to lock or release the pulley 21, The bar 33 projectshori zontally to a position where it can be conn veniently reached bythe` operator of the machine and easily manipulated to .set or releasethe clutch.

@ne end ot the sleeve 22 is provided with a head 34 and a screw 35 ismounted therein and carries a block 3G. A shatt 3T is mounted in thesleeve 22 and is geared at 39 to one end of the screw said sha'lt havingan operating' crank 39 by means ot which the attendant may revolve theshaft 3T and the screw 35 and move the block 36 back and forth on thescrew to change its position with respect to the longitudinal axis otthe supporting` sleeve and regulate the stroke or the pitman connectedtherewith. 40 is a pitman rod mounted at one end on the block 36 andhaving a fork 4l at its opposite end that is pivotally connected at 42with a quadrant 43 mounted to rock on a pivot 44. The' teeth of thequadrant engage a pinion 45 on a shaft 46 to which la shea-ve 4T issecured. A. cable 48 engages this sheave, passes around smaller sheaves49 at each end of the machine and forms an endless belt connection foroperating the sanding' head or shoe. The position ot the sheaves 49 isindicated in Figure 6, where one of them is shown supported by a bracket50 secured to thevmachin'e frame. n n

The sanding` head, r t'erring` to Figures 6 and 7, comprises a Jframe 51having a universal joint portion 52 whereon the shoe 53 which engagesthe sanding belt is mounted. Brackets 54 are mounted on the frame 51 andanti-friction bearings such as wheels 55 and 56 are supported in saidbrackets in planes substantially at rile-ht angles to each other. Aclamp device 51a is provided at each end ot the frame 51 torconnectingit with the operating1 cable 48, so that the rock ing of theslieave 47 and the forward and backward movement of the cable 48 will betransmitted. to the sandinghead and shoe and through the shoe and thesanding` belt to the surface of the work. y

1 provide an improved 'form of guide bar in connection with this headand shoe, consistinp; preferably of upper and lower members or bars 57and 572L held in parallel relation by blocks 58 interposed between them.The anti-'friction bearings 55operate on the opposing inner :faces ofthe bars 57 and 5" and the bearings 56 operate on the longitudinal edgesof the lower` bar 57e, and thereby theA shoe frame ispheld and guidedwith an even uniform strelre throughout its movement, K Y

The pressure of the sanding` belt is varied by the vertical adjustmentof the guide bar 57 and this l prefer to accomplish by providing shafts59 mounted in themaehine frame at one end and having hubs 59LL thereonprovided with depending arms 50 connected by a bar 61 to insure uniformstroke of the arms. Arms 62 are secured to the shaft 59 and links 63 arepivotally connected with the ends ot said arms 62 and are alsopivotall)l connected with links 64 which are mounted at the lower end onthe guide bar 5T and pivotally connected at their opposite endswith armsG5 that are mounted on the hubs 59'7 thus conipleting` a. parallel linkmovement which will. insure a vertical stroke ot the `guide bar insteador an oscillating one. [i strap 65 is mounted on the middle portion otthe guide bar and is slida-bly connected by means ot a slot 57 and pinGS with a lever 69 that is mounted at one end on the machine trame andhas a hand grip 70 at its opposite end to be grasped by the operator:tor depressing or raising` the guide bar. The lever (i9 also preferablyhas a slot il to receive a guide pin 72 on a bracket 73, said pin andslot serving` to guide the lever in its movement and enable theattendant to agpl7 thel pressureot the guide bar the desired point onthe sanding belt.

W hen the clutch is thrown out or" engagement, the momentum or" thesanding head is checked by a brake on the sheave 47, as illustrated inFigure 2, wherein a bar Z 4 is pivoted at 75 to the machine iframe.WWhen the clutch operatingbar 38 is pulled toward the operator torelease the clutch, the cross bar 75, pivoted on the clutch operatingbar33 and bar 'T4 will :torce the block 77 into trictional eno'agement withthe sheave 47. thus checking movement of the cable and sanding head.

ln the operation of the machine, the attendant drawing the table to itsouter position will place the work thereon, having` previously adjustedthe table to the desired elevatiom then will push the table and the workin under the sanding` belt and graspin the pressure lever.y will applythe desired pressure to the sanding' shoe, which in turn will transmitit through the belt to the surface oit the work. At any time during' theprogress of the work the stroke or travel out the head may be varied bythe adiustment of' the block connecting` the pitman rod with itsoperating mechanism. rThe guide bar comprising` as described, the upperand lower portions with the 'frame oi the sanding` or pressure shoemounted between them, insures even, uniform travel ot the shoe and anequal pressure at all points on the sand-- ing belt. y

l claim as my invention: Y l. 1n asanding machine, a guide barcomprising'iiat upper and lower plates arranged in parallel relation andspaced apart and means at intervals securing' the middle portions ofsaid plates together, an unobstructedv passage being' provided betweensaid plates upon each side of said securing means, a sanding headarranged `beneath the lower member of said guide bar and havinganti-"friction bearings on thelongitudinal edges of said lower member,and

similar bearings between said members, and a sanding shoe connected withsaid head.

2. ln a sanding machine, a guide bar comprising upper and lower membersspaced apart and secured together in parallel relation, a sanding headhaving brackets arranged to straddle said guide bar and bearings carriedby said brackets and fitting between the upper and lower members of saidbar to slide thereon, and a shoe connected with'said sanding head.

3. The combination, with a guide bar having upper and lower sections, ofa sanding head comprising a frame extending transversely of said bar andbeneath the same and having upwardly projecting brackets, anti-frictionwheels mounted in said frame to bear on the longitudinal edges of saidbar and similar wheels mounted in said brackets in planes at rightangles substantially to the other wheels and fitting between the upperand lower sections of said bar.

et. ln a sanding machine, a guide bar composed of upper and lowermembers having opposing guiding surfaces, a sanding head comprising aframe having bearing on the longitudinal edges of one of said guide barmembers and also having brackets to straddle said guide bar, saidbrackets having bearing on the opposing inner sur-` faces of said. guidebar members, and a sanding shoe connected with said frame.

5. In a machine of the class described, a guide bar comprising upper andlower members spaced apart and secured together in parallel relation andhaving opposing guiding surfaces, a sanding head extending transverselyof said bar beneath the same and having upwardly projecting membersbearing on the opposing guiding surfaces, and means mounted on said headand bearing on the longitudinal edges of one of said members for holdingsaid head against lateral movement.

6. The combination, with a guide bar having upper and lower membersprovided with opposing guiding surfaces, of a head having anti-frictionbearings on said opposing surfaces, said head also having bearings on alongitudinal edge of said guide bar.

7. A guide-bar comprising upper and lower members spaced apart andsecured t0- gether in parallel relation and having opposing guidingsurfaces, a head having means fitting between the upper and lowermembers of said bar and having anti-friction bearings on said surfaces,and a shoe connected With said head.

In witness whereof, I have hereunto set my hand this 18th day of April,1921.

JOHN GALBRAITH.

